/*
 * Cell Broadband Engine OProfile Support
 *
 * (C) Copyright IBM Corporation 2006
 *
 * Author: Maynard Johnson <maynardj@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

/* The code in this source file is responsible for generating
 * vma-to-fileOffset maps for both overlay and non-overlay SPU
 * applications.
 */

#include <linux/mm.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/elf.h>
#include <linux/slab.h>
#include "pr_util.h"


void vma_map_free(struct vma_to_fileoffset_map *map)
{
        while (map) {
                struct vma_to_fileoffset_map *next = map->next;
                kfree(map);
                map = next;
        }
}

unsigned int
vma_map_lookup(struct vma_to_fileoffset_map *map, unsigned int vma,
               const struct spu *aSpu, int *grd_val)
{
        /*
         * Default the offset to the physical address + a flag value.
         * Addresses of dynamically generated code can't be found in the vma
         * map.  For those addresses the flagged value will be sent on to
         * the user space tools so they can be reported rather than just
         * thrown away.
         */
        u32 offset = 0x10000000 + vma;
        u32 ovly_grd;

        for (; map; map = map->next) {
                if (vma < map->vma || vma >= map->vma + map->size)
                        continue;

                if (map->guard_ptr) {
                        ovly_grd = *(u32 *)(aSpu->local_store + map->guard_ptr);
                        if (ovly_grd != map->guard_val)
                                continue;
                        *grd_val = ovly_grd;
                }
                offset = vma - map->vma + map->offset;
                break;
        }

        return offset;
}

static struct vma_to_fileoffset_map *
vma_map_add(struct vma_to_fileoffset_map *map, unsigned int vma,
            unsigned int size, unsigned int offset, unsigned int guard_ptr,
            unsigned int guard_val)
{
        struct vma_to_fileoffset_map *new = kzalloc(sizeof(*new), GFP_KERNEL);

        if (!new) {
                printk(KERN_ERR "SPU_PROF: %s, line %d: malloc failed\n",
                       __func__, __LINE__);
                vma_map_free(map);
                return NULL;
        }

        new->next = map;
        new->vma = vma;
        new->size = size;
        new->offset = offset;
        new->guard_ptr = guard_ptr;
        new->guard_val = guard_val;

        return new;
}


/* Parse SPE ELF header and generate a list of vma_maps.
 * A pointer to the first vma_map in the generated list
 * of vma_maps is returned.  */
struct vma_to_fileoffset_map *create_vma_map(const struct spu *aSpu,
                                             unsigned long __spu_elf_start)
{
        static const unsigned char expected[EI_PAD] = {
                [EI_MAG0] = ELFMAG0,
                [EI_MAG1] = ELFMAG1,
                [EI_MAG2] = ELFMAG2,
                [EI_MAG3] = ELFMAG3,
                [EI_CLASS] = ELFCLASS32,
                [EI_DATA] = ELFDATA2MSB,
                [EI_VERSION] = EV_CURRENT,
                [EI_OSABI] = ELFOSABI_NONE
        };

        int grd_val;
        struct vma_to_fileoffset_map *map = NULL;
        void __user *spu_elf_start = (void __user *)__spu_elf_start;
        struct spu_overlay_info ovly;
        unsigned int overlay_tbl_offset = -1;
        Elf32_Phdr __user *phdr_start;
        Elf32_Shdr __user *shdr_start;
        Elf32_Ehdr ehdr;
        Elf32_Phdr phdr;
        Elf32_Shdr shdr, shdr_str;
        Elf32_Sym sym;
        int i, j;
        char name[32];

        unsigned int ovly_table_sym = 0;
        unsigned int ovly_buf_table_sym = 0;
        unsigned int ovly_table_end_sym = 0;
        unsigned int ovly_buf_table_end_sym = 0;
        struct spu_overlay_info __user *ovly_table;
        unsigned int n_ovlys;

        /* Get and validate ELF header.  */

        if (copy_from_user(&ehdr, spu_elf_start, sizeof (ehdr)))
                goto fail;

        if (memcmp(ehdr.e_ident, expected, EI_PAD) != 0) {
                printk(KERN_ERR "SPU_PROF: "
                       "%s, line %d: Unexpected e_ident parsing SPU ELF\n",
                       __func__, __LINE__);
                goto fail;
        }
        if (ehdr.e_machine != EM_SPU) {
                printk(KERN_ERR "SPU_PROF: "
                       "%s, line %d: Unexpected e_machine parsing SPU ELF\n",
                       __func__,  __LINE__);
                goto fail;
        }
        if (ehdr.e_type != ET_EXEC) {
                printk(KERN_ERR "SPU_PROF: "
                       "%s, line %d: Unexpected e_type parsing SPU ELF\n",
                       __func__, __LINE__);
                goto fail;
        }
        phdr_start = spu_elf_start + ehdr.e_phoff;
        shdr_start = spu_elf_start + ehdr.e_shoff;

        /* Traverse program headers.  */
        for (i = 0; i < ehdr.e_phnum; i++) {
                if (copy_from_user(&phdr, phdr_start + i, sizeof(phdr)))
                        goto fail;

                if (phdr.p_type != PT_LOAD)
                        continue;
                if (phdr.p_flags & (1 << 27))
                        continue;

                map = vma_map_add(map, phdr.p_vaddr, phdr.p_memsz,
                                  phdr.p_offset, 0, 0);
                if (!map)
                        goto fail;
        }

        pr_debug("SPU_PROF: Created non-overlay maps\n");
        /* Traverse section table and search for overlay-related symbols.  */
        for (i = 0; i < ehdr.e_shnum; i++) {
                if (copy_from_user(&shdr, shdr_start + i, sizeof(shdr)))
                        goto fail;

                if (shdr.sh_type != SHT_SYMTAB)
                        continue;
                if (shdr.sh_entsize != sizeof (sym))
                        continue;

                if (copy_from_user(&shdr_str,
                                   shdr_start + shdr.sh_link,
                                   sizeof(shdr)))
                        goto fail;

                if (shdr_str.sh_type != SHT_STRTAB)
                        goto fail;

                for (j = 0; j < shdr.sh_size / sizeof (sym); j++) {
                        if (copy_from_user(&sym, spu_elf_start +
                                                 shdr.sh_offset +
                                                 j * sizeof (sym),
                                           sizeof (sym)))
                                goto fail;

                        if (copy_from_user(name, 
                                           spu_elf_start + shdr_str.sh_offset +
                                           sym.st_name,
                                           20))
                                goto fail;

                        if (memcmp(name, "_ovly_table", 12) == 0)
                                ovly_table_sym = sym.st_value;
                        if (memcmp(name, "_ovly_buf_table", 16) == 0)
                                ovly_buf_table_sym = sym.st_value;
                        if (memcmp(name, "_ovly_table_end", 16) == 0)
                                ovly_table_end_sym = sym.st_value;
                        if (memcmp(name, "_ovly_buf_table_end", 20) == 0)
                                ovly_buf_table_end_sym = sym.st_value;
                }
        }

        /* If we don't have overlays, we're done.  */
        if (ovly_table_sym == 0 || ovly_buf_table_sym == 0
            || ovly_table_end_sym == 0 || ovly_buf_table_end_sym == 0) {
                pr_debug("SPU_PROF: No overlay table found\n");
                goto out;
        } else {
                pr_debug("SPU_PROF: Overlay table found\n");
        }

        /* The _ovly_table symbol represents a table with one entry
         * per overlay section.  The _ovly_buf_table symbol represents
         * a table with one entry per overlay region.
         * The struct spu_overlay_info gives the structure of the _ovly_table
         * entries.  The structure of _ovly_table_buf is simply one
         * u32 word per entry.
         */
        overlay_tbl_offset = vma_map_lookup(map, ovly_table_sym,
                                            aSpu, &grd_val);
        if (overlay_tbl_offset > 0x10000000) {
                printk(KERN_ERR "SPU_PROF: "
                       "%s, line %d: Error finding SPU overlay table\n",
                       __func__, __LINE__);
                goto fail;
        }
        ovly_table = spu_elf_start + overlay_tbl_offset;

        n_ovlys = (ovly_table_end_sym -
                   ovly_table_sym) / sizeof (ovly);

        /* Traverse overlay table.  */
        for (i = 0; i < n_ovlys; i++) {
                if (copy_from_user(&ovly, ovly_table + i, sizeof (ovly)))
                        goto fail;

                /* The ovly.vma/size/offset arguments are analogous to the same
                 * arguments used above for non-overlay maps.  The final two
                 * args are referred to as the guard pointer and the guard
                 * value.
                 * The guard pointer is an entry in the _ovly_buf_table,
                 * computed using ovly.buf as the index into the table.  Since
                 * ovly.buf values begin at '1' to reference the first (or 0th)
                 * entry in the _ovly_buf_table, the computation subtracts 1
                 * from ovly.buf.
                 * The guard value is stored in the _ovly_buf_table entry and
                 * is an index (starting at 1) back to the _ovly_table entry
                 * that is pointing at this _ovly_buf_table entry.  So, for
                 * example, for an overlay scenario with one overlay segment
                 * and two overlay sections:
                 *      - Section 1 points to the first entry of the
                 *        _ovly_buf_table, which contains a guard value
                 *        of '1', referencing the first (index=0) entry of
                 *        _ovly_table.
                 *      - Section 2 points to the second entry of the
                 *        _ovly_buf_table, which contains a guard value
                 *        of '2', referencing the second (index=1) entry of
                 *        _ovly_table.
                 */
                map = vma_map_add(map, ovly.vma, ovly.size, ovly.offset,
                                  ovly_buf_table_sym + (ovly.buf-1) * 4, i+1);
                if (!map)
                        goto fail;
        }
        goto out;

 fail:
        map = NULL;
 out:
        return map;
}